Availability of virtual threads made me want to switch from reactive Spring Cloud Gateway to it’s MVC version. Migration of most of the code was easy (changing some classes and method names, moving routes configuration from spring.cloud.gateway.routes to spring.cloud.gateway.mvc.routes), but one thing that doesn’t seem to work is simple discovery client for load balancing for routes.

Every time I try to access route that is using load balancing I get error like:

org.springframework.web.client.HttpServerErrorException: 503 Unable to find instance for dashboard-backend

How can I use simple discovery client work in Spring Cloud Gateway MVC? (I don’t want to use external discovery clients.)

Configuration that I use:

spring:
  application:
    name: test-application
  threads:
    virtual:
      enabled: true
  cloud:
    loadbalancer:
      configurations: health-check
    discovery:
      client:
        simple:
          instances:
            dashboard-backend:
              - instanceId: dashboard-backend-1
                serviceId: dashboard-backend
                uri: http://localhost:8081
              - instanceId: dashboard-backend-2
                serviceId: dashboard-backend
                uri: http://localhost:8082
    gateway:
      mvc:
        routes:
          - id: dashboard-backend
            uri: lb://dashboard-backend
            predicates:
              - Path=/api/**